I have one Office 365 Account which ist User and Admin where I Set 2FA as active. After Reset of My mobile Phone i am now Not able to Setup My Account because i have no Access to My QR Code anymore.

I need urgent Support HereI cannot Login into My Account anymore because Always the 2fa Pops Up but i cannot proceed because of the inactice authenticator App. Others Options are mit enabled for My Account.

You will need to sign in as a separate global administrator user in order to disable MFA on your existing account. If you only have one global administrator account, you'll need to sign in as a regular user and log a support request with Microsoft to have them help you elevate that user to a global admin role. This process is typically (and surprisingly) fairly painless - You may be required to prove you own the tenant by, say, adding a TXT record to your Office365 custom domain, but it shouldn't take more than one phone call/20 minutes.

You can then use this newly elevated user to disable MFA on your existing account. Once you've disabled MFA, you can go here;